r600/sb: Fix constant-logical-operand warning.

sb/sb_bc_parser.cpp:620:27: warning: use of logical '&&' with constant operand [-Wconstant-logical-operand]
        if (cf->bc.op_ptr->flags && FF_GDS)
                                 ^  ~~~~~~
sb/sb_bc_parser.cpp:620:27: note: use '&' for a bitwise operation
        if (cf->bc.op_ptr->flags && FF_GDS)
                                 ^~
                                 &
sb/sb_bc_parser.cpp:620:27: note: remove constant to silence this warning
        if (cf->bc.op_ptr->flags && FF_GDS)
                                ~^~~~~~~~~

Fixes: da977ad9 ("r600/sb: start adding GDS support")
Signed-off-by: Vinson Lee <vlee@freedesktop.org>
Reviewed-by: Dave Airlie <airlied@redhat.com>
(cherry picked from commit cc33621e)